Atomic layer deposition (ALD) and chemical vapor deposition (CVD) are two exemplary methods used in semiconductor fabrication to deposit thin films on a substrate. ALD and CVD processes generally include introducing a process gas to a process chamber in which a substrate, such as a semiconductor substrate, is supported on a substrate support.
Heated ceramic substrate supports or plates have been found useful in at least ALD and CVD processing. However, the inventors have observed that the heater temperature can be non-uniform across the surface of the heater due to the configuration of the process chamber. For example, in some chamber configurations, the inventors have observed that the temperature can be non-uniform over the area of the heater that covers a pin lift hoop opening in the bottom of the chamber, and a slit valve opening in the side of the chamber that is used for loading and unloading substrates for processing.
Thus, the inventors have provided an apparatus and processing chamber for improving substrate temperature uniformity.